1. Field of the Invention
The present invention relates to a method of manufacturing a photo interrupter to detect presence and absence or passing of an object with non-contact and a photo interrupter manufactured by the method of manufacturing.
2. Description of the Related Art
It is known that a photo interrupter is used in the field of information equipment, for example, in in-vehicle air conditioner panel operating switches, navigation control units, DVD recorders, digital cameras, printers, PC peripheral instruments or the like and can reliably detect a position or presence and absence or the like of an object with non contact by receiving light from a light-emitting element by a light-receiving element.
In recent years, a microminiature photo interrupter is widely used accompanying the further miniaturization of and thinning of information equipment; in addition, such a compact photo interrupter is often surface-mounted on a motherboard of the information equipment or the like. In a surface-mount type photo interrupter, accuracy of detecting a position of an object is directly influenced by variation in a position of mounting the photo interrupter on the motherboard. Accordingly, it is necessary to position the photo interrupter on the motherboard accurately.
A conventional photo interrupter includes a board on which a light-emitting element is mounted, a board on which a light-receiving element is mounted, a generally U-character-shaped frame having element frames on which the boards are mounted and configured to form a light path from the light-emitting element to the light-receiving element, and a positioning member formed to project from a lower surface of the frame, the positioning member being inserted into a hole provided in a motherboard or the like to position the interrupter on the motherboard (for reference, see Japanese Patent Application Publication No. 2000-12892, page 3 of the specification, FIG. 1).
On the other hand, there is known a method of manufacturing a plurality of photo interrupters at the same time by use of a collecting board on which a plurality of light-emitting elements are mounted, a collecting board on which a plurality of light-receiving elements are mounted, and a frame assembly in which a plurality of U-character-shaped frames are connected, forming a photo interrupter assembly by adhering the collecting board on which the plurality of light-emitting elements are mounted and the collecting board on which the plurality of light-receiving elements are mounted, to upper and lower surfaces of the frame assembly, respectively, and dividing the formed photo interrupter assembly by dicing into an individual photo interrupter (for reference, see Japanese Patent No. 3640456, pages 3 to 4 of the specification, FIG. 2).
However, in the conventional photo interrupter as disclosed in Japanese Patent Application Publication No. 2000-12892, despite the accomplishment of a high accuracy in positioning of the photo interrupter on the motherboard by the positioning member provided on the frame, because the positioning member is formed separately from the frame, an extra process is required to make a plurality of positioning members and a troublesome operation is required to mount very small positioning members on the frame one by one. Consequently, increased manufacturing cost due to increased manufacturing processes or the like is unavoidable.
Furthermore, in the conventional manufacturing method for the photo interrupter as disclosed in Japanese Patent No. 3640456, because a mounting surface of the photo interrupter, to be placed on a motherboard, is a surface cut by dicing, it is not possible to provide a positioning pin or the like on the cut surface. Therefore, there is a problem that variation in a position of attaching the photo interrupter to the motherboard occurs, resulting in a photo interrupter of low accuracy.